black diamond

Short definition from Wiktionary

Noun

1. 1
   Hematite.
2. 2
   Anthracite.
3. 3
   Carbonado, a natural diamond that is black in color.
4. 4
   A black synthetic diamond, specifically a CVD polycrystalline diamond or HPHT polycrystalline compact diamond.
5. 5
   Boron carbide.
6. 6
   A member of the new affluent black middle class in South Africa, characterized by conspicuous consumption.
7. 7
   A symbol representing a steep and relatively difficult trail, typically of a 40% gradient or above.